Polypeptides solubilized from B. subtilis spore coats and fractionated by polyacrylamide gel electrophoresis will be compared by peptide mapping techniques. The presence of dityrosine cross links will be investigated. Purified acid-soluble B. subtilis spore proteins (ASSPs) will also be compared by peptide mapping. Antisera raised against different fractions of ASSPs and spore coat polypeptides will be employed in detecting cross-reactive materials synthesized during sporulation. In this way the kinetics of synthesis and maturation of precursors of unique spore components will be determined. These techniques will be employed to determined the effect on synthesis of spore-specific components of shift of temperature sensitive sporulation (Spo ts) mutants to non-permissive temperature. We hope in this way to clarify the apparent sporulation-specific translational defect in erythromycin-resistant mutants.